{"product_id":"sierra-18-3555-marine-thermostat-160f-replaces-mercruiser-99155a1-fits-1998-newer-gm-v-6-v-8-with-closed-cooling","title":"Sierra 18-3555 Thermostat, 160 Degree, for Mercruiser 7.4L MIE 454 V-8 Closed Cooling 1996-1997","description":"\u003cp\u003eThe Sierra 18-3555 is a 160 degree marine thermostat engineered for Mercruiser 7.4L MIE 454 cubic inch V-8 stern drive engines equipped with closed (fresh water) cooling. It mounts at the engine block and regulates coolant flow through the closed cooling loop, opening at 160 degrees Fahrenheit to keep the engine operating in its correct temperature range for efficient combustion and reduced wear. The thermostat is finished in white and installs using the standard engine block mount configuration found on this Mercruiser engine family. It is built to meet or exceed the performance of the original equipment component it replaces, making it a straightforward like-for-like replacement for a worn, stuck, or failed thermostat. This part is specific to the 7.4L EFI MIE 454 V-8 configuration with closed cooling covering the 1996-1997 model years and the serial number range noted in the fitment section below, so confirm your engine's cooling system type and serial number before ordering. Keeping the thermostat within spec protects against overheating and helps the engine reach efficient operating temperature faster after startup.\u003c\/p\u003e\u003ch3\u003eSpecifications\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eBrand:\u003c\/strong\u003e Sierra\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eManufacturer Part Number:\u003c\/strong\u003e 18-3555\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTemperature Rating:\u003c\/strong\u003e 160 degrees Fahrenheit\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCooling System Type:\u003c\/strong\u003e Closed Cooling (Fresh Water Cooling)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eColor:\u003c\/strong\u003e White\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMounting Type:\u003c\/strong\u003e Engine Block Mount\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWeight:\u003c\/strong\u003e 0.07 pounds\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eUPC:\u003c\/strong\u003e 030999316035\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eFitment\u003c\/h3\u003e\u003cul\u003e\u003cli\u003eMercruiser MIE 7.4L EFI 454 cubic inch V-8, Closed Cooling, 1996-1997, serial numbers F874815 through K999999\u003c\/li\u003e\u003c\/ul\u003e\u003ch3\u003eReplaces (OEM)\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003eGLM 13040\u003c\/li\u003e\n\u003cli\u003eMallory 9-43001\u003c\/li\u003e\n\u003cli\u003eMallory 9-43016\u003c\/li\u003e\n\u003cli\u003eMercruiser Stern Drive 991551\u003c\/li\u003e\n\u003cli\u003eMercruiser Stern Drive 99155A1\u003c\/li\u003e\n\u003cli\u003eMercruiser Stern Drive 99155T2\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eFrequently Asked Questions\u003c\/h3\u003e\u003cp\u003e\u003cstrong\u003eWhat temperature does the Sierra 18-3555 thermostat open at?\u003c\/strong\u003e The Sierra 18-3555 is rated to open at 160 degrees Fahrenheit, which is the standard operating temperature for the Mercruiser closed cooling systems it is designed for.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhich engines does the 18-3555 thermostat fit?\u003c\/strong\u003e This thermostat fits Mercruiser MIE 7.4L EFI 454 cubic inch V-8 engines with closed cooling, covering the 1996-1997 model years within serial number range F874815 through K999999.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eDoes the 18-3555 work on standard raw water cooled engines?\u003c\/strong\u003e No. The 18-3555 is built for the closed (fresh water) cooling version of the Mercruiser 7.4L EFI MIE 454 V-8; engines with standard raw water cooling use a different Sierra thermostat.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat OEM part numbers does the Sierra 18-3555 cross-reference?\u003c\/strong\u003e The 18-3555 interchanges with GLM 13040, Mallory 9-43001 and 9-43016, and Mercruiser Stern Drive 991551, 99155A1, and 99155T2.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eIs the Sierra 18-3555 a genuine Mercruiser part or aftermarket?\u003c\/strong\u003e The 18-3555 is a Sierra aftermarket thermostat manufactured to meet or exceed the performance of the original Mercruiser equipment it replaces, not a Mercruiser-branded part.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eHow much does the 18-3555 thermostat weigh?\u003c\/strong\u003e The Sierra 18-3555 thermostat weighs 0.07 pounds.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat color is the 18-3555 thermostat?\u003c\/strong\u003e The 18-3555 has a white finish.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eHow does the 18-3555 mount to the engine?\u003c\/strong\u003e It uses an engine block mount configuration, installing directly at the engine block on the closed cooling loop of the Mercruiser 7.4L MIE 454 V-8.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat is included when I order the 18-3555?\u003c\/strong\u003e The listing includes one Sierra 18-3555 160 degree marine thermostat.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhy would I replace my thermostat with the 18-3555?\u003c\/strong\u003e A stuck, corroded, or out-of-spec thermostat can cause a Mercruiser 7.4L MIE 454 V-8 to run too hot or too cold; the 18-3555 restores the correct 160 degree opening point for the closed cooling system.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eIs there a UPC for the Sierra 18-3555?\u003c\/strong\u003e Yes, the Sierra 18-3555 thermostat carries UPC 030999316035.\u003c\/p\u003e","brand":"Sierra","offers":[{"title":"Default Title","offer_id":48988153184475,"sku":"SIE-18-3555","price":20.39,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0839\/7586\/4539\/files\/SIE-18-3555_lg__34723.1558126853.500.750.jpg?v=1785188005","url":"https:\/\/www.goodvibesmarina.com\/products\/sierra-18-3555-marine-thermostat-160f-replaces-mercruiser-99155a1-fits-1998-newer-gm-v-6-v-8-with-closed-cooling","provider":"Good Vibes Marina","version":"1.0","type":"link"}